Electronic text input devices, such as portable communication devices including PDAs, mobile phones, etc., may receive text input based on a user contacting the device in some manner, for example, by depressing a single key of a keyboard or touching a discrete area on a touchscreen of the device. The buttons or discrete areas may be mapped to text characters, such as alphanumeric characters, and the user may perform a sequence of individual contact actions to enter desired text content, such as a word, into the device. Some devices may also provide for simultaneous touch input, such as by simultaneously selecting a shift key and a letter on a keyboard that is displayed on a screen.
In typical portable electronic text input devices, a keyboard or touchscreen is positioned on a surface that will face the user (“front surface”) when the user uses the device, and one or more other input elements, such as a text scrolling button or other depressable buttons, are positioned on a side surface or the front surface. Based on the relatively small size of the typical device, and also the location of the keyboard or touchscreen on the front surface, the user may comfortably hold the device so as to enter text, either by resting the back surface of the device on several fingers, other than the thumb, of one or both hands, or by gripping one side surface with the thumb of one hand and an opposing side surface with several fingers of the same hand.
When the device is held as described above using both hands, the user usually enters text by performing a contact action with the thumb of either hand. Alternatively, when the device is held with only one hand, the user usually enters text by performing a contact action using a single finger, such as the thumb or index finger, of the opposing hand. The relatively very small size of the keys or touch sensitive areas on the device that would be individually contacted using a single finger of a user's hand, however, limits the speed with which text can be entered by the user with a high level of accuracy.
In addition to physical and virtual keyboards, other text entry devices also exist. For example, a stenotype machine allows a user to press multiple keys to enter certain text characters, symbols or various predefined words or phrases.